Trigger: Real-Time Alerts is a free finance app that lets you monitor the stock market real-time. However, unlike most other similar apps, the app also lets you set specific conditions so that it could alert you whenever the condition is met. Available both on iOS and Android, Trigger is probably the app you always wanted to keep a watchful eye on the stock market. Custom triggers can also be shared via email, text, and other tools. If you’ve been in stock trading for some time, you would probably know that no broker offers such custom market triggers.